Heat-recoverable articles such as a heat-shrinkable tubing are used for, for example, protection, insulation, waterproofing, and corrosion prevention of a connected portion of insulated electric wires, a wiring terminal, a metal tube, or the like and for packaging of commercial products. For example, when a connected portion of insulated electric wires is covered with a heat-shrinkable tubing and heated, the heat-shrinkable tubing shrinks so as to conform to the shape of the connected portion and comes in close contact with the connected portion. Thus, the heat-shrinkable tubing can protect the connected portion. For such heat-recoverable articles, for example, it is desirable that the heat-recoverable articles do not thermally shrink at an ambient temperature before heating, and that, during thermal shrinkage, an excessively high thermal shrinkage temperature will have no adverse effect on an article to be protected.
For example, for a cylindrical, heat-recoverable article, it is desirable that the heat-recoverable article does not split in the axial direction due to stress in a circumferential direction during shrinkage. To meet this desire, a heat-recoverable article having perforations in an axial direction thereof has been proposed in which stress in a circumferential direction is released as a result of the perforations opening during thermal shrinkage, thereby preventing the heat-recoverable article from splitting (refer to Japanese Unexamined Patent Application Publication No. 2007-62825).